Reconfigurable semiconductor devices, such as field programmable gate arrays (FPGAs), are drawing attention these days. A rewritable logical operation circuit included in such a semiconductor device is formed with a circuit that forms a truth table having a certain number (typically, three to six) of inputs, or a network of look-up table circuits.
As will be described later, in a conventional semiconductor device, the outputs of the respective basic logic elements and the flip-flops in each logical block are connected to specific wiring lines, and therefore, the same number of wiring lines as the total number of the outputs of the basic logic elements and the flip-flops disposed in each logical block are prepared in parallel. Because of this, a large circuit area is required, which results in increases in the production costs.